Android中EditText的字数统计

public class WriteActivity extends Activity {

private TextView wordAmount;
private EditText contentEditText;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_write);
wordAmount = (TextView) findViewById(R.id.word_amount);
contentEditText = (EditText) findViewById(R.id.content_edittext);
contentEditText.addTextChangedListener(new TextWatcher() {//Adds a TextWatcher to the list of those whose methods are called whenever this TextView's text changes.

private CharSequence temp;//A CharSequence is a readable sequence of char values. This interface provides uniform, read-only access to many different kinds of char sequences.

@Override
public void beforeTextChanged(CharSequence s/*之前的文字内容*/,  int start/*添加文字的位置(从0开始)*/, int count, int after/*添加的文字总数*/){

}

@Override
public void onTextChanged(CharSequence s/*之后的文字内容 */, int start/*添加文字的位置(从0开始)*/, int before/*之前的文字总数*/, int count) {
temp = s;
}

@Override
public void afterTextChanged(Editable s/*之后的文字内容*/) {
wordAmount.setText("" + temp.length());
}
});
}
}